Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B25—HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
  • B25B—TOOLS OR BENCH DEVICES NOT OTHERWISE PROVIDED FOR, FOR FASTENING, CONNECTING, DISENGAGING OR HOLDING
  • B25B27/00—Hand tools, specially adapted for fitting together or separating parts or objects whether or not involving some deformation, not otherwise provided for
  • B25B27/14—Hand tools, specially adapted for fitting together or separating parts or objects whether or not involving some deformation, not otherwise provided for for assembling objects other than by press fit or detaching same
  • B25B27/18—Hand tools, specially adapted for fitting together or separating parts or objects whether or not involving some deformation, not otherwise provided for for assembling objects other than by press fit or detaching same withdrawing broken threaded parts or twist drills
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B25—HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
  • B25B—TOOLS OR BENCH DEVICES NOT OTHERWISE PROVIDED FOR, FOR FASTENING, CONNECTING, DISENGAGING OR HOLDING
  • B25B13/00—Spanners; Wrenches
  • B25B13/48—Spanners; Wrenches for special purposes
  • B25B13/50—Spanners; Wrenches for special purposes for operating on work of special profile, e.g. pipes

Definitions

• This invention relates to extractors for removing broken threaded fasteners such as broken bolts, and more particularly, to a broken fastener extractor comprising a drill head with a collet to grab the bolt, and including guide means for starting the drill in the center of the broken bolt.
• the bolt or stud will be considered as having right-hand threads —as by far the dominant number of bolts and studs do— and hands of threads and directions of rotation will be used as is appropriate for broken bolts with right-hand threads. This is in no way limiting; if the stud has left-hand threads, the hands of thread and directions of rotation will be opposite those taught herein.
• inventions which combine a drill for forming a bore within a broken right-hand bolt stud and a bolt stud extractor for removing the broken bolt in a single combination tool, thereby enabling one to remove the broken bolt in one operation.
• the lower portion of the tool is provided with a drill bit having a cutting edge threaded with a pitch in a left hand direction (opposite to the threads of the broken right-hand bolt stud being extracted) .
• the drill bit body is on the lower end of a threaded shaft the upper portion of which is structured to be connected to a suitable counterclockwise hand tool or power-driven tool.
• a bolt extractor collet is threadedly mounted on the right- hand threaded shaft above the drill bit.
• the diameter of the lower portion of the gripping collet is less than the outside diameter of the drill bit which enables the collet to enter the bore formed in the broken bolt stud.
• the extractor collet is formed of a series of longitudinal segments separated by slots.
• the upper portion of the drill bit head is formed with an expander surface structured to engage and expand the longitudinal segments of the expander collet.
• the upper end of the shaft of the extractor is connected to a suitable hand or power drive tool.
• the drill bit engages the stud and rotates to form a bore within the body of the broken bolt stud.
• the extractor collet which is threadedly mounted on the drill shaft, engages the interior of the hole being bored in the stud.
• the extractor collet engages the interior of the hole being bored in the stud.
• the extractor collet engages the expander surface on the drill bit body. This causes the segments to spread, thereby securely gripping the interior bore in the broken bolt stud just formed by the drill bit.
• the upper end of the expander collet serves to provide an additional surface for gripping by a hand tool, if needed, and also provides a means for separating the expander collet from the broken bolt stud after the stud has been removed. This is done by rotating the collet and stud member in opposite directions.
• the present invention relates to improved guide means to guide the drill bit in making its initial contact with the stud so that the drilled bore will be in the center thereof.
• This guide means is in the form of an enlargement on the upper end of the collet which, when the collet is inverted, engages in the aligned opening of an adjacent flange as the drilled hole is started.
• the invention relates to improved gripping means on the outside of the collet preferably in the form of left-hand threads or fluttings.
• FIG. 1 is a perspective view of the bolt extractor combination tool of the present invention
• Fig. 2 is an exploded view of Fig. 1
• Fig. 3 is an enlarged top plan view of Fig. 1
• Fig. 4 is an enlarged bottom view of Fig. 1
• Fig. 5 is a view of the combination tool of the present invention used to remove a broken bolt stud showing the collet inverted and the guide means in use in the opening of an adjacent flange, the tool initially penetrating the stud,
• Fig. 5a is an enlarged sectional view taken on the line 5a- 5a of Fig. 5, Fig. 6 shows the drilling proceeding with the collet right side up, and
• Fig. 7 is a view of the tool extracting the broken bolt stud.
• Figs. 1 to 4 illustrate the threaded broken bolt extractor tool 10 of the present invention.
• the extractor 10 includes a drill bit 12 having a left-hand or counterclockwise cutting pitch.
• the drill bit 12 includes a body portion 14 and cutting edges 16.
• the body portion 14 of the drill bit 12 is formed with a sloping expander surface 18 and is integrally attached to a threaded shaft 20.
• the expander surface 18 slopes outwardly from the zone where the drill body 14 meets the threaded shaft 20 toward the cutting edges 16 of the bit 12.
• the upper end of the shaft 20 is preferably hexagonal (Fig. 3), formed with flat surfaces 22 to facilitate the gripping of the extractor tool 10 by a suitable driving means such as a counterclockwise power tool chuck or hand-driven wrench or drill.
• the extractor tool 10 includes an extractor collet 24 formed of a tapered body 26 terminating in a series of segments 28 separated by longitudinal slots 30.
• the collet 24 is provided with a series of helically disposed gripping flutes or left- hand threads 32 having sharp edges and extending from the bottom, to a point adjacent the top of each of the segments 28.
• the separation of each of the segments 28 by slots 30 provides a degree of resiliency to the end of the segments which proves useful in gripping the broken bolt stud as described hereinbelow.
• the extractor collet 24 includes an internal threaded bore 34 which permits the collet to be reciprocally and rotatably movable along the longitudinal axis of the threaded shaft 20.
• the upper section of the expander collet 24 includes an enlarged drive head 36 having a plurality of flat sides 38 making it suitable to be gripped and rotated by a suitable tool. Intermediate the flat sides, the head is rounded as at 40, as shown, to less than the diameter of an opening 0 in a mating flange F (Fig. 5) .
• a broken bolt stud 50 is shown embedded within a threaded bore 52 in a supporting surface 54.
• the extractor tool 10 of the present invention is mechanically coupled to the chuck 46 of a suitable hand or power tool. It will be appreciated that the flat surfaces 22 on the shaft 20 are gripped by the chuck in a conventional, well-known manner to transfer a rotational driving force from the drive tool to the extractor tool 10. Assuming again that the broken stud 50 has right-hand threads, the driving tool is rotated in a left-handed or counterclockwise direction to drive the drill bit 12 into the stud 50.
• the collet 24 Prior to inserting the shaft 20 into the chuck of a drill, the collet 24 is inverted (Fig. 5) so that when the extractor is inserted in the bolt hole, the rounded portions 40 of the enlarged drive head fit closely inside the walls of opening 0 in the flange F.
• the collet and the bit will be close together (i.e., closer than shown in Fig. 5) so that the collet will engage the wall of opening O as the bit first engages the stud 50.
• the collet centers the extractor including the drill bit 12 so that the bore will be started in the center of the stud.
• the rounded portions 40 help the drill operator keep the drill tip from drifting "downhill" as the drilling commences.
• the dimensions are preferably such that the collet 24 rotates freely in the opening O with only a small clearance.
• the extractor is raised from opening 0, and the shaft taken out of the drill chuck.
• the collet is rotated off the shaft 20, inverted to the position shown in Fig. 6 and the extractor is reinstalled into the chuck.
• Drilling is continued.
• the extractor collet 24 is carried on the threaded shaft near the bit.
• the ends of the segments 28 eventually enter the bore 42 in the stud 50 and engage the side walls thereof.
• continued rotation of the driving tool causes the drilling to stop and the extractor collet 24 moves along the threads toward the drill bit 12 as the bit raises.
• the segments 28 move outwardly as they ride up on the expander surface 18 thereby securing the grip on the interior walls of the bore 42 formed within the stud 50.
• the gripping is enhanced by the left-hand threads 32 on the outside of the collet which tend to bite into the stud around the drilled bore 42. Thereafter, continued rotation of the driving tool unthreads the stud 50 out of the larger bore 52 in the supporting surface 54.
• the drive head 36 on the extractor collet 24 may be used to either obtain a firmer grip against the interior wall surface of the bore 42 if, for example, a hand-driven drive means is used, or the drive head may be used to disengage the extractor collet from the broken stud once the stud is removed.

Landscapes

• Mechanical Engineering (AREA)
• Engineering & Computer Science (AREA)
• Hand Tools For Fitting Together And Separating, Or Other Hand Tools (AREA)
• Drilling Tools (AREA)
• Pharmaceuticals Containing Other Organic And Inorganic Compounds (AREA)
• Medicines Containing Plant Substances (AREA)
• Sampling And Sample Adjustment (AREA)
• Surgical Instruments (AREA)
• Dental Tools And Instruments Or Auxiliary Dental Instruments (AREA)
• Load-Engaging Elements For Cranes (AREA)
• Gripping Jigs, Holding Jigs, And Positioning Jigs (AREA)
• Processing And Handling Of Plastics And Other Materials For Molding In General (AREA)
• Earth Drilling (AREA)
• Acyclic And Carbocyclic Compounds In Medicinal Compositions (AREA)
• Cleaning In General (AREA)
• Drilling And Boring (AREA)
• Gripping On Spindles (AREA)

Priority Applications (5)

Applications Claiming Priority (4)

Publications (1)

Family

ID=27028522

Family Applications (1)

Country Status (14)

Cited By (1)

Families Citing this family (44)

Citations (2)

Family Cites Families (2)

• 1990
  • 1990-06-13 US US07/537,243 patent/US5031487A/en not_active Expired - Lifetime
  • 1990-10-24 AU AU67224/90A patent/AU620779B2/en not_active Ceased
  • 1990-10-24 DE DE69009455T patent/DE69009455T2/de not_active Expired - Fee Related
  • 1990-10-24 JP JP2515613A patent/JPH0815710B2/ja not_active Expired - Fee Related
  • 1990-10-24 AT AT90916914T patent/ATE106301T1/de not_active IP Right Cessation
  • 1990-10-24 EP EP90916914A patent/EP0451256B1/en not_active Expired - Lifetime
  • 1990-10-24 BR BR909006985A patent/BR9006985A/pt not_active IP Right Cessation
  • 1990-10-24 KR KR1019910700681A patent/KR0163012B1/ko not_active IP Right Cessation
  • 1990-10-24 WO PCT/US1990/006018 patent/WO1991006399A1/en active IP Right Grant
  • 1990-10-25 IE IE384990A patent/IE64664B1/en not_active IP Right Cessation
  • 1990-10-26 PL PL90287524A patent/PL166483B1/pl unknown
  • 1990-10-29 CA CA002028800A patent/CA2028800C/en not_active Expired - Fee Related
  • 1990-10-31 MX MX023157A patent/MX167306B/es unknown
• 1991
  • 1991-07-01 NO NO912580A patent/NO177221C/no not_active IP Right Cessation

Patent Citations (2)

Non-Patent Citations (1)

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